For example, an RD of Rs. 5000 each month for a period of 1.5 years at interest 7.5% p.a. compounded quarterly yields on maturity and amount of:

FV(7.5%/4, 4 * 1.5, -5000 * (3 + (7.5%/2))) = Rs. 95,504.78The above formula is a general formula and individual banks might use a slightly different formula. For example, the Indian Banks' Association uses the following formula for computing the maturity value where interest is compounded quarterly (Source: http://www.iba.org.in/formula.asp):Maturity amount = ((Value of each instlament) * ((1+i)^n-1))/(1-(1+i)^(-1/3)),where i = (Rate of interest) /4 and n = number of quarters.Hence, taking the same example of RD of Rs. 5000 each month for a period of 1.5 years at interest 7.5% p.a. compounded quarterly, the maturity value, according to this formula is:((5000) * ((1+(7.5%/4))^6-1))/(1-(1+(7.5%/4))^(-1/3)) = Rs. 95502.35Extending the formula to other compounding periods:For Monthly compounding: Maturity amount = ((Value of each instlament) * ((1+i)^n-1))/(1-(1+i)^(-1))where i = (Rate of interest)/12 and n = number of months.

For half-yearly compounding: Maturity amount = ((Value of each instlament) * ((1+i)^n-1))/(1-(1+i)^(-1/6))where i = (Rate of interest)/2 and n = number of years * 2.

Download the following app on your android phone to compute the maturity amount for fixed and recurring deposits: http://goo.gl/olkbN.